An optical module includes: a wiring substrate having an electrode pad on a main surface thereof; an optical waveguide disposed on the main surface of the wiring substrate; an optical semiconductor device mounted on a main surface of the optical waveguide, and having a connection pad disposed on a main surface on an optical waveguide side of the optical semiconductor device; and an electrically conductive member for providing electrical connection between the electrode pad and the connection pad. The optical waveguide has a hole passing therethrough in its thickness direction to leave the electrode pad exposed. The connection pad includes a projection which is at least partly inserted in the hole. The conductive member is disposed inside the hole, and makes connection with the projection and the electrode pad.